[CH3:1][C:2]([S:5]([NH2:7])=[O:6])([CH3:4])[CH3:3].[C:8]1(=O)[CH2:11][CH2:10][CH2:9]1.[Cl-].[Na+]>C1COCC1.[O-]CC.[Ti+4].[O-]CC.[O-]CC.[O-]CC>[C:8]1(=[N:7][S:5]([C:2]([CH3:4])([CH3:3])[CH3:1])=[O:6])[CH2:11][CH2:10][CH2:9]12-methylpropane-2-sulfinamide (4.32 g, 35.7 mmol) and titanium(IV) ethoxide (16.3 g, 71.3 mmol) were added sequentially to a solution of cyclobutanone (2.5 g, 35.7 mmol) in THF (102 ml) at 22° C. The mixture was stirred at 60° C. for 5 h. The reaction mixture poured over a stirring saturated aqueous sodium chloride solution (60 mL). Celite was added to the suspension and it was filtered through a pad of Celite, washing with ethyl acetate (300 mL). The filtrate was washed with brine and the organic layers were combined and dried with anhydrous sodium sulfate. The dried solution was filtered and the filtrate was concentrated, yielding an oil which was purified on silica gel (Biotage, 25 g column, EtOAc/hexanes gradient, fraction collection at λ=254 nm) to give the expected product N-cyclobutylidene-2-methylpropane-2-sulfinamide (4.6 g, 27 mmol, 74% yield) consistent by NMR. 1H NMR (400 MHz, CHLOROFORM-d) δ 3.59-3.22 (m, 2H), 3.21-3.03 (m, 2H), 2.12 (t, J=8.2 Hz, 2H), 1.24 (s, 9H).
読み込み中…
